问题
解答题
计算: (1)90
(2)99×101×10001 |
答案
(1)90
×891 9 8 9
=
×90×9+1 9 89×9+8 9
=8099
;80 81
(2)99×101×10001=(100-1)(100+1)×10001
=(10000-1)(10000+1)
=100000000-1
=9999999
=108-1;
计算: (1)90
(2)99×101×10001 |
(1)90
×891 9 8 9
=
×90×9+1 9 89×9+8 9
=8099
;80 81
(2)99×101×10001=(100-1)(100+1)×10001
=(10000-1)(10000+1)
=100000000-1
=9999999
=108-1;